The present invention relates to an apparatus for drying a web of textile material and, more particularly, an apparatus for drying a continuously travelling web of textile material following coating or dyeing of the textile material.
The coating or dyeing of the material is typically accomplished by one of a variety of conventionally-known methods such as immersion of the textile material in a liquor bath or spraying of the textile material with a liquid. Following this type of processing of a textile material, which will be hereinafter referred as wetting of the textile material, a controlled drying operation is performed to dry the applied coating or drying material on the textile material to a predetermined degree. Additionally, it is conventionally known to separate a traveling web of textile material into a number of webs prior to or following wetting of the material. For example, German patent document DE A 32 02 923 discloses a device for separating a textile web into two more webs, the device disposed between the device for wetting the textile web and two pairs of heating rollers adapted for applying heat to the two newly-formed webs following wetting of the original textile web to thereby effect drying of the webs. The two heating rollers of each respective pair of heating rollers are arranged in a generally horizontal plane and the two respective pairs of heating rollers are arranged in generally superposed relationship to one another with their horizontal planes parallel to one another.
The two separated webs are guided between the two pairs of heating rollers before each separated web initially engages the first roller of the respective pair of heating rollers around which it travels during the drying process. The two separated webs accordingly travel, without any appreciable support, over a distance of approximately two meters between the nip formed by the squeezing rollers at the wetting device and their respective locations at which the separated webs initially engage a heating roller. This relatively lengthy travel extent of the wet separated webs undesirably creates conditions in which the individual yarns of the separated webs may twist or snarl. Another disadvantage of the arrangement disclosed in the German patent document is that the two pairs of heating rollers, which are arranged after the squeezing rollers relative to the direction of travel of the textile web, require a relatively large amount of space. If one considers the space requirements of the measuring apparatus, squeezing rods, and other devices which are typically disposed between the squeezing rollers and the heating rollers, a total extent of at least 500 millimeters must be reckoned with between the nip of the squeezing rollers and the initial engagement locations on the heating rollers of the separated webs.
An arrangement has also been proposed in which the two pairs of heating rollers are arranged in a common plane above the squeezing rollers. However, since it is desirable that the two separated webs travel generally the same total distance between the nip of the squeezing rollers and their respective initial engagement with the heating rollers so as to avoid uneven drying of the separated webs, it is generally necessary that change of direction rollers be disposed between the nip and the heating rollers to insure that the two separated webs of the textile web travel relatively the same distance. However, the addition of the change of direction rollers adds to the travel extent through which the separated webs travel while being generally unsupported, thereby creating the undesirable conditions mentioned above in which twisting and snarling of individual fibers occurs.
A further proposed arrangement of the heating rollers includes two heating rollers of pair of heating rollers arranged in superposed relation to one another with the two pairs of heating rollers disposed side by side to one another. However, this arrangement disadvantageously increases the height of the web drying apparatus. Moreover, the total unsupported distance over which the separated webs travel in this arrangement can in practice exceed the travel distances traveled by the separated webs handled by the device disclosed in German patent document DE A 32 02 923 discussed above. Additionally, a change of direction roller must typically be disposed between the pair of squeezing rollers and the heating rollers if the pair of squeezing rollers are arranged in superposed relation to one another (i.e., if the textile web travels in a generally horizontal plane through the nip created between the pair of squeezing rollers). Otherwise, the pair of squeezing rollers must be arranged in side by side relation to one another (i.e., the textile web must travel in a vertical plane through the nip formed between the pair of squeezing rollers).
If the textile web is to be separated into four separate webs, it is generally necessary that the textile web be separated into two separate webs before any wetting of the textile web occurs, thereby necessitating the provision of two wetting devices. If the heating rollers are arranged in one of the previously proposed arrangements as discussed above, it can been seen that the space requirements correspondingly increase when a textile web is separated into four instead of two webs and, moreover, the same disadvantages of undesired twisting or snarling of individual yarns still occur. Accordingly, the need exists for an apparatus for drying of a textile web, or other webs separated therefrom, following wetting of the textile web which optimally reduces space requirements and which minimizes the extent to which the textile web or separated web travel in unsupported manner between the nip of the squeezing rollers and their initial engagement with the heating rollers.